Sortation systems, such as mail piece sorting equipment, are often large and complex systems having a large number of sortation bins. To sort mail for delivery by a postal service or private carrier may involve equipment having hundreds of sortation bins. This is to enable sortations that will organize the mail pieces into a delivery order sequence for the mail delivery person. The sortation process is often a multiple pass radix-type sortation algorithm process. Sortation equipment may be manufactured with a number of sortation bins to accommodate the largest number of sortation separations that may be required. In such cases, many of the sortation bins are not required for the most of the sortation applications. The equipment and the required space for the equipment can be very costly. Accordingly, it is desirable to reduce the size and cost of sorting equipment as well as to increase the equipment flexibility.
Reductions in the size of sortation equipment have utilized techniques where the size of the sortation bins are reduced by employing overflow bins. In such case, an overflow sortation bin accommodates mail being processed when the original destination sortation bin is filled. The overflow sortation bin is assigned during each sortation run as a designated overflow bin for a single original destination sortation bin. This allocation remains for the duration of the sortation run. As a result, an estimate is required before the sortation process pass commences as to which original destination sortation bins may become filled and will require during the sortation process run one or more overflow sortation bins. When this estimate is inaccurate, the sortation process may have to be stopped when an original destination sortation bin becomes filled and no overflow sortation bin has been provided. Sortation equipment of this type also does not provide flexibility for mail pieces that may have been roughly sorted prior to the commencement of a sortation run and thereby over flow different original destination sortation bins throughout the course of a sortation run.
When mail pieces are roughly grouped as mail to a given geographical area, such as Connecticut, New York and New Jersey, such mail can be combined in a sortation run. Mail pieces from each state are grouped together when loaded into the equipment for sortation run. Moreover, mail even when not roughly sorted, may be created in a way that establishes a rough grouping. If this mail is processed in a single sortation run, the sortation equipment must have a sufficient number of sortation bins to accommodate all the destinations sortation bins required for the sortation separation. Moreover, if the sortation equipment operator does not remove the mail pieces as the sortation bins approach their maximum capacity, the sortation equipment will either stop or, in a more difficult situation, jam. A jam of the sortation equipment will require operator intervention to restart the machine by clearing all of the jammed mail pieces, which also may be mutilated.